Hewlett-Packard said on Tuesday the British company Autonomy it bought for $9.7 billion last year lied about its finances, resulting in a massive write-down of the value of the business.

HP said it took an $8.8 billion charge related to its acquisition of Autonomy, as citing "serious accounting improprieties," as it swung to a fourth-quarter loss.

"HP is extremely disappointed to find that some former members of Autonomy's management team used accounting improprieties, misrepresentations and disclosure failures to inflate the underlying financial metrics of the company, prior to Autonomy's acquisition by HP. These efforts appear to have been a willful effort to mislead investors and potential buyers, and severely impacted HP management?s ability to fairly value Autonomy at the time of the deal. We remain 100 percent committed to Autonomy and its industry-leading technology," HP said in a statement.

HP says that the majority of the $8.8 billion impairment charge, more than $5 billion, is linked to the "accounting improprieties, misrepresentation and disclosure failures" discovered by an internal investigation by HP and forensic review into Autonomy's accounting practices prior to its acquisition by HP.

HP launched its internal investigation into these issues after a senior member of Autonomy?s leadership team came forward, following the departure of Autonomy founder Mike Lynch, alleging that there had been a series of questionable accounting and business practices at Autonomy prior to the acquisition by HP.

HP now believes that Autonomy was substantially overvalued at the time of its acquisition due to the misstatement of Autonomy's financial performance, including its revenue, core growth rate and gross margins, and the misrepresentation of its business mix.

HP has referred this matter to the US Securities and Exchange Commission's Enforcement Division and the UK's Serious Fraud Office for civil and criminal investigation. The company says it will aggressively pursue this matter in courts in the months to come.